After taste is quite common according to Charlie especially with high doses.
( In Switzerland it is available in 10K units per cc and in NA it is available in 1K per cc).
For 20 years I have received B 12 shots and never experienced after taste.
Methylcobalamin injectable is preferred for proper absorption. The cost differential is conciderable however the literature is convincing IMO. ( I am by no means an expert but feel my nervous system depends on this supplement and maybe cause I am wired for sound almost 24/7 ie… my needs are high and I utilize it big time? who knows?)
Lidocaine as an additive into the B12 helps with the sting and soreness.